This invention relates to a device for, and methods of, trapping and removing emboli in a body vessel. The device and method of this invention are especially adapted to be used in preventing emboli in blood from passing through a vessel such as an artery.
In recent years, numerous procedures have been adapted for expanding blood vessels (e.g. arteries), at the positions of lesions in the blood vessels, so that blood can flow through the blood vessels without obstruction from the lesions. In the process of expanding such blood vessels at the positions of the lesions, embolic particles/debris may become detached from the lesions and enter the bloodstream and subsequently migrate through the patient's vasculature to cut off or reduce the amount of oxygenated blood being supplied to sensitive organs such as the brain and heart, which may induce trauma.
Procedures have also been adapted in recent years for preventing embolic debris from flowing through the vessels in the direction of the blood flow. For example, filters have been provided for trapping the emboli. When lesions develop in the carotid artery of a patient, the placement of a filter in the patient's vasculature can somewhat reduce the movement of emboli to blood vessels leading to the patient's brain, thereby preventing strokes from occurring.
Such filters are usually delivered in a collapsed position through the patient's vasculature and are then expanded once in place in the patient's blood vessel to trap the emboli. After emboli have been trapped, the filter is collapsed and removed (with the trapped emboli) from the vessel. Unfortunately, it is possible for some of the trapped emboli to escape from the filter during the time that the filter is being collapsed and/or removed from the blood vessel. When an interventional procedure is being performed in a carotid artery, even a trace release of emboli can be damaging. For these reasons, attempts to treat lesions in the carotid arteries have been somewhat limited due to the danger presented if all of the embolic debris is not collected during the procedure.
Therefore, in light of the above, it would be desirable for a device and method which can be utilized to treat an occluded vessel and trap any emboli that may be formed during the vascular procedure. Such a device and method must also prevent the emboli from escaping from the filter during the time that the filter is being collapsed and/or removed from the blood vessel (e.g. the carotid arteries). Although considerable progress has been made in recent years in providing a satisfactory filter, it would still be desirable to provide a filter which is simple, cost efficient and trustworthy in construction, is easy to deploy and remove from the patient's vasculature with little or no adverse impact or immunological response to the patient. Also, such a device should have a thin profile to reach tight distal lesions in the patient's vasculature.